Rewrite ${((5^{-10})(8^{9}))^{-5}}$ in the form ${5^n \times 8^m}$.
Explanation: ${ ((5^{-10})(8^{9}))^{-5} = (5^{(-10)(-5)})(8^{(9)(-5)})} $ ${\hphantom{ ((5^{-10})(8^{9}))^{-5}} = 5^{50} \times 8^{-45}} $